Fibrous compound of thermoplastic



Patented May 11, 1937 FIBROUS COMPOUND OF THERMOPLASTIC RUBBER DERIVATIVES James A. Merl-ill, Akron, Ohio, assignor to Wingfoot Corporation, Wilmington, Del., 2, corporation of Delaware No Drawing. Application May 4, 1934, Serial tives in the manufacture of molded products, the condensation derivative in solid form.

The preferred method of this invention in- Wood pulp, such as sulfite wood pulp or pulp volves the preparation of an emulsion of a soluproduced by other processes or pulps made from tion of a condensation derivative of rubber, by Other materials than Wood Suehes Vegetable the use of a solution of a rubber derivative obbers and fibrous cotton materials such, for extained in the course of the manufacture of the mp as the fibers r c v om u autocondensation derivative, although condensation mobile tires, etc. may be utilized in carrying out derivatives of rubber however formed may be the D C Both e S v and the amount of brought into solution and the solutions thus 019 solvent employed may be varied with the various tained utilized in carrying out the process, fibrous substances utilized in order to control, at

15 According to the preferred method of proceleast to Some t, e degree o impregnation dure the reaction mixture obtained by treating and to assure adhesion of the solution of the a solution of rubber in an organic solvent such as Condensation derivative of the rubber to the r benzene, with a reagent such as a halide of an brous material. Orga ic Solvents, Such as amphoteric metal or compound thereof, is intizene, chloroform, petrol u d s, 8, p

mately mixed with fibrous material which has tha, etc y e ilize wh r cond n i n debeen wet with water, When the condensation rivatives soluble in such solvents are employed. derivative of the rubber in solution in the organic In general benzene y be Considered e mOSt solvent is thus applied to the wet fibrous material satisfactory solvent for this use. it impregnates the fibrous material at least to It appea s that the reagents used i producing the extent of entering between the fibers. The Condensat o derivatives of bb ay be adhesion between the solution and the fibrous vided generally into two classes, one of which material is such that on filtering, the condensaincludes Compounds Such as Sulfuric acid, Which tion derivative is entirely, or largely held by the Very po b y do not Produce any intermediate fibrous material and the excess water with little p odu but Convert the rubber directly to the or no condensation derivative passes through the condensation derivative; and other products such filter. The separation of the excess water from as the halides of amp te e metals a 00 the fibrous mass and condensation rubber depounds t e which pp y first Produce rivative may be effected in any suitable manner. a metal compound which must be further treated For example, the mass where wood fiber is emto produce the condensation derivative. For

ployed may be fed onto a screen such as that example, when a solution of rubber is treated used in the manufacture of paper to form a mat with tin tetrachloride or chlorostannic acid it or bat. The solvent and remaining water may app a s that a compound, bably havin the be vaporized and the fibers and rubber derivative formula (C5H8)x-S1IC14, is first formed and that then heated and pressed to form a sheet or panel to obtain the condensation derivative of rubber,

in or object of any desired shape. this compound must be treated with a substance The fibrous mass obtained may be pressed and such as water, acetone or alcohol. If a product after pressing heated to remove the remaining of the first class such as sulfuric acid is to be solvent. The fibrous material may be agitated used it is preferable to produce the condensation while part or all of the solvent and water are derivative in solution in a solvent such as benbeing evaporated. The fibrous mass may ad zone and use the reaction mixture directly, after vantageously be shaped somewhat before refirst neutralizing the free acid if necessary, in the moving the solvent, and then after removing manufacture of the fibrous compositions. With the solvent it may be brought to the final shape compounds of the Second class the first p of desired by heating and pressing. After removthe reaction is also advantageo y carried out 59 ing the water and solvent in any desired manner in solution in an organic solvent. The reaction the resulting mass may be molded with heat and mixture which includes the metal-containing pressure. During the molding operation the concompound formed is then used directly, and when densation derivative of rubber becomes plastic mixed with water the metal-containing comand with pressure further impregnation of the pound is broken down and the condensation de- .55 fibers is attained. In any event, by applying the rlvative produced,

2 Claims.

This invention relates to articles made from a fibrous material and a condensation derivative of rubber. More particularly it relates to the use of emulsions of solutions of such rubber derivacondensation derivative of rubber in solution to the fibers more uniform and thorough distribution of the condensation derivative among the fibers is obtained than would be possible by using The water present in the emulsion employed performs one or more useful functions. Organic solvents are, of course, relatively expensive and by mixing with water a smaller amount of the expensive organic solvent may be used to treat an amount of fibrous material, which without the use of water would require a larger amount of solvent. To illustrate, if one were to attempt to wet a large amount of a dry fibrous material With the condensation derivative dissolved in a small amount of solvent it would be diflicult to obtain anything like a uniform distribution of the solution over the fibrous material. By first wetting the material with water and then adding a small amount of the condensation derivative, this condensation derivative may be quite uniformly spread over a relatively large amount of the fibrous material.

In the process involving the use of metallic compounds, such as tin tetrachloride, in the manufacture of the condensation derivative of the rubber, the Water performs an additional function when the reaction mixture comprising the metal-containing derivative of rubber is mixed with the wet fiber, namely the decomposition of the metal-containing derivative of the rubber and the formation of the condensation derivative.

The process may, for example, be carried out as follows: Pale crepe rubber plasticized to a plasticity of 300 (as determined by a Williams plastometer) is dissolved in suflicient benzene to form a 10% solution. Ten per cent (by weight) of; hydrated chlorostannic acid is added to the cement and the mixture heated under .a reflux cqndenser at a temperature at or near the boilture may be poured into considerable water, and

ing point for several hours. The properties of the condensation derivative obtained will vary, dependingupon the extent to which the chlorostannic acid acts upon the rubber. For example, a condensation derivative. with a softening point o f ,0 C. may be obtained, or by longer heating or heating to a higher temperature a harder condensation, derivative of rubber may be produced, such for example, as one with a softening point around 100 C. With shorter heating a productwith a softening point of about 30 C. may be obtained. When the action of the chlorostannic acid on the rubber has progressed to thepoint required to produce. a condensation derivative of rubber having the desired properties the reaction is terminated by the addition of a small amount ofv water or sodium hydroxide. This reaction mixture may be used to treat the fibrousmaterial. If desired, the reaction mixthe. emulsion thus formed may be used to treat the. wet. fibrous material, and where a suiiiciently. large amount of water is used it. may be mixed with dry fibrous. material.

The fibrous material may, for example, be the cotton fibers. reclaimed from rubber tires. This fibrous ,material may be treated with sufficient water to form a. thin slurry and the benzene solution resulting from the treatment of the rubber with the chlorostannic acid may be added to the; slurry with sufficient agitation or mixing to obtain substantially uniform distribution of the condensation derivative in the fibrous material.

The amount of the condensation derivative of the rubber added to a given quantity of the fibrous material may vary over a. considerable range. The final product may contain 15% of fibrous material, althoughmore generally 25% or. 40%

would be employed, and as much:.as 75.-80% or higher may be used. A mixture of substantially equal parts (by weight) of the fibrous material and the condensation derivative of rubber will be satisfactory for many purposes.

For example, 80 pounds of the fibrous material obtained in the reclamation of rubber from old tires may be mixed with 100 gallons of water. The fibrous material and Water are thoroughly agitated to form a slurry. To this 301 gallons of the benzene solution of the reaction product of chlorostannic acid on rubber obtained as above described are added with agitation to distribute the rubber derivative substantially homogeneously throughout the mass. The water acts on the metal-containing rubber derivative and pro duces the condensation derivative which, when prepared by this process, will contain a small amount of combined chlorine. Other condensation derivatives which contain no chlorine but are substantially 100% hydrogen and carbon may be used.

The slurry thus obtained is treated for the removal of water. This may be done by centrifuging or filtering as by passing through the screen or Web of a paper machine. In this way a large amount of the water is removed. The product obtained contains some water and volatile solvent which should be recovered in any commercial application of the process. The bat of fibrous material obtained by screening is advantageously heated to remove the solvent and Water and then while still warm, with additional heating if necessary, or after first cooling and then after again heating, it is shaped with pressure. For example, the bat of material obtained by screening may be heated to form a dry, loosely-knit panel, which may be sub-divided and then shaped into an object, such .as a receptacle, by the application of heat and pressure. bat from the paper machine while still containing the solvent and moisture may first be shaped to form a blank for insertion in a molding machine and this blank may then be heated to remove solvent and moisture before the final molding. operation. Many diiferent varieties of objects of quite different shapes may be made.

The molded articles after the final molding operation are advantageously dipped in chlorine water for .a few minutes to prevent the surface from being tacky and to make them oil resistant.

Wheredesirable plasticizers, etc. and filling ma terials may be added. Rubber, balata, and the like may be added by dissolving in the solutionof the condensation derivative before adding to be colored and where desired different colors mayi be used with each.

A chlorine-containing condensation derivative. may be obtained by treating the rubber with a, mixture of hydrochloric acid and the halide of. an amphoteric metal, instead of using. chlorostannic acid. Where a hydrocarbon condensation. derivative of rubber is desired tin tetrachloride is advantageously employed by causing it to react on a heated rubber cement.

chloride, etc. may be usedin forming. such condensation derivatives of rubber.

The

Other halides of amphoteric metals such as iron chloride, chromic I claim:

1. The method of forming fiber-containing products which comprises treating rubber in solution in a volatile solvent with a halide of an amphoteric element and without removing the resulting rubber derivative from solution mixing it with water and fibrous material and thereafter separating the water and volatile solvent and shaping the fibrous mass.

2. The method of forming fiber-containing products which comprises treating rubber in solution in a volatile solvent with chlorostannic acid and without removing the resulting rubber derivative from solution mixing it with water and fibrous material and thereafter separating the water and volatile solvent and shaping the fibrous mass.

JAMES A. MERRILL. 

